Dental syringe



June 25, 1929. A. E. SMITH DENTAL SYRINGEV Filed Dec 17; 1927 2 Sheets-Sheet HM W. Z uhl l 'nnufi- HJLJTLTLLL V. M 3

M N H WT INVENTOR.

ARTHUR E. SMITH ATTORNEY.

June 25, 1929. 1 E sM'n-H 1,718.60]

DENTAL SYRINGE Filed Dec. 17 1927 2 Sheets-Sheet 2 .65. INVENTOR.

flRTHl/R E. SM/TH ATTdkNEY.

ARTHUR. E. SMITH, 015 L98 ANGELES CALIFORNIA.

DENTAL SYRINGE.

. Application filed December 17, 1927. Serial No. 249,797.

This invention relates to improvements hypodermic syringes. I The general object of this invention is to provide an improved syringe wherein the substance to be ejected is contained in a cartridgelike ampule having a slidable stopper thereln which is adapted to act as 8 131513011 to expel the contents ofthe ampule, and the nvention particularly aims to provide an improvedmeans for automatically and correctly POSI- tioning the ampule in the syringe.

Another object of this invention 1s to provide a syringe of the class described having an ejector plunger rod which is adapted to enter the ampule to move the stopper and to provide an improvedmeans for maintaining the ejector plunger and the stopper in correct alignment.

Other objects of this invention will be apparent from the following description taken in connection with the accompanying drawings wherein:

Fig. 1 is a central longitudinal section through my improved syringe showing an ampule therein and showin the plunger rod as engaging the stopper 0 the ampule an,

' about to move the stopper to expel the contents of the ampule.

Fig. 2 is a side elevation partly in section of my improved syringe showing the relative positions of the various elements when the contents of the ampule have been expelled.

Fig. 3 is a view similar to Fig. 2 showin a small sized ampule used in my improve syringe.

Fig. 4 is a detail central longitudinal section through the tip of the syringe.

Fig. 5 is a side view of an ampule such as shown in use in my syringe in Figs. 1 and 2. Fig. 6 is an enlarged detail central longitudinal section through the stopper of the ampule shown in Fig. 5.

Fig. 7 is a modified form of ampule such as may be used in my improved syrin e.

Fig. 8 is a View similar to Fig. 7 s owing the manner of preparing the ampule for use.

Fig. 9 is an enlarged detail central longi-' tudinal section through the stopper of the ampule shown in Figs. 7 and 8- Fig. 10 is an enlarged view partly in section of the transfer probe preferably used A in connection with the modified form of ampule.

Referring to the drawlngs by reference characters, I have indicated a hypodermic syringe embodying the features of my'mvention generally at 10. This syringe comprises a hollow body portion or barrel 11 having screw threads 12 provided at one-end and hav- 1 ing a finger grip cross bar 13 provided in the barrel 11 between the cross bar 13 and the threads 12.

The end of the syringe opposite the cross 'bar 13 is provided with a cap 16 which is in threaded engagement with the screw threads 5 beyond the end of the cap and may be either threaded or tapered as shown.

As clearly shown in Fig. 4 the tip 19 is provided with a tapered recess 23 which communicates with an aperture 24 which extends through the reduced end 22. A hypodermic needle indicated generally at 25 is adapted to be positioned on the reduced end 22 of the tip 19 as shown;

A positioning member 26 is adapted to be nserted into the barrel'll at the opposite end of the syringe from the cap 16. This member 26 has a conical recess 27 and a central aperture 28 in which is positioned an ejector or plunger r6d 30. The plunger rod 30 ineludes at one end an enlarged thumb piece 31 i and at the opposite end is provided with an enlarged head 32 and a conical recess 33. At the apex of the conical recess in the positioning member 26 I provide a recess 34 which is ofda size to receive the head 32 of the plunger ro The centering device 26 is of a size to frictionally engage the inner side. walls of the barrel 11 with a fit so that it will remain in any position to which it is moved and the plunger rod 30 isadapted to move freel. in the aperture 28 of the centering device. The centering or positioning member, which is preferably of metal, is a thin cylinder and somewhat resilient so that although the member may be moved by grasping it its side wall fits the barrel so that normally it is held in adjusted position.

To prepare the syringe 10 for use it is only necessary to pull the plungerrod 30 towards the open end of the barrel 11 until the head 32enters the recess 34' and engages the posi- 3 tioning member 26, whereupon on further movement of the plunger rod the positioning the ampule which I- have shown in' use in my.

improved syringe. in Figs. 1 and 2. This ampule includes a body portion or compartment 36 which is closed at one end by a bulbous portion 37 and at the opposite end-is provided with a tapered neck 38 which terminates in a closed tip 39. At the uncture of the bulbous portion 37 and the compartment 36 a constricted portion is provided as indicated at 40. Surrounding the tapered neck 38 I provide a resilient collar 41 which is preferably made of a good grade of rubber.

To render thebulbous portion 37 readily separable from the compartment 36 I preferably weaken the constricted portion 40 by scoring it or etching it as at 42 and to render the tip 39 readily separable from the neck 38 I may also weaken it by etching it just below the resilient collar as at 43. In the compart ment 36 and adjacent the constricted portion 40 I provide a stopper 44 which is shown in detail in Fig. 6.

The stopper 44 is preferably made of a good grade of rubber and includes abody portion.

45 having a protruding tip- 46 extending therefrom. At the juncture of the body portion and the tip a semi-circular groove 47 is provided so that when the stopper is used as a piston to expel the contents of the ampule the pressure exerted upon the stopper by the contents of the ampule will cause the lower edge of the stopper to tightly grip the inner side walls of the ampule and prevent any of the ampule contents from passing the stopper.

Grooves 48 are preferably provided in the sides of .the body portion 45 and a lubricant 49, such as glycerine, may be placed in the grooves so as to lessen the vfriction of the stopper against the side walls of the ampule when it is moved therein.

Positioned on the top face ofthe bod portion 45 I provide a metallic disk, or was er 50 which includes a central conical boss 51 and a plurality of depressed lips 52 which are arranged in the body 45. The disk 50 is joined to the stopper 44 at the time of moulding the stopper and the lips 52 become imbedded in the body of the stopper and retain the disk 50 in position on the stopper.

- To prepare the ampule 35 for use in my syringe 10 it is only "necessary to break-the bulbous portion '37 off at the etching 42 and to break the tip 39 off at the etching 43.

To insert the ampule in the syringe the centering device 26 and theplunger rod 30 are removed as previously described. The ampule is then inserted in the syringe barrel 11 so that the resilient collar 41 is positioned in the tapered recess 23 of the tip 19 and then the positioning member 26 and the plunger rod are again operatively positioned in the syringe barrel 11. The centering device is then moved towards the ampule until it abuts the end of the ampule and centers it. Then the plunger rod 30 is moved through the opening at the constriction 40 until 1t abuts the stopper 44. When the head 32 of the plunger rod abuts the stopper the lower face thereof contacts with the disk 50 and the central conical boss 51 of the disk 50 is positioned in the conical recess 33 in the end of the plunger rod, thus the end of the plunger rod is prevented from skidding to one side and t1lting the stopper.

Upon further movement of the plunger rod 30 towardsthe cap 16 it will force the stopper '44 towards the tapered neck 38 of the ampule and cause the stopper to act as a piston to expel the contents of the ampule into the hypodermic needle 25.

The pressure required to move the stopper 44 to expel the contents of the ampule will wedge the collar 41 in the tapered recess 23 of the tip 19 and form a fluid tight seal between the end of the ampule and the syringe.

In Figs. 7 and 8 I have indicated at 55 a modified form of ampule for use in my syringe. Thisampule 55 as shown comprises two separate containers or compartments 56 and 57 which are preferably made of glass, fused together and constricted at their juncture as indicated at 58.

The end of the compartment 56 is closed by a bulbous portion 59 and at the juncture of the compartment 56 and the bulbous portion 59 a constricted portion is provided as indicated at 60. The end of the compartment 57 is provided with a tapered neck 61 which terminates in a closed tip 62.

Between the two compartments 56 and 57 and at the constriction 58 a metallic seal 63 is provided. This metallic seal is preferably a disk shaped platinum partition and is fused in position when manufacturing the ampule. In thecompartment 57 and adjacent the constriction 58 I provide a stopper indicated generally at 64 and shown in detail in Fig. 9. This stopper is preferably positioned in the compartment 57 before the tapered neck 61 and tip 62 are formed. Surrounding the tapered neck 61 I provide a resilient collar 65 which is preferably made of a good grade of rubber.

To render the bulbous portion 59 readily separable from the compartment 56 I preferably weaken the. constricted portion 60 by scoring or etching it as at 66. To render the compartments 56 and 57 readily separable from one another I may weaken the constriction 58 by etching it as at 67 and to render the tip 62 readily separable from the neck 61 I may also weaken it by etching it just below the resilient collar as at 68.

The contents of the compartment 56, such as the vehicle 69 which may be distilled water, is preferably placed therein before the bulbous portion 59 is formed closed and the connriaeei tents of the compartment 57, such as the drug 70, is placed therein before the tip 62 is closed.

Also, before thetip 62 is closed the compartment 57 is preferably exhausted to a state of partial vacuum.

The stopper 64 is preferably made of a good grade of rubber and includes a body portion 71 having a concaved lower face as indicated at 72 and having a conical boss7 3 on its opposite'face'. Grooves 74 are preferably provided in the sidesof the body 71 and a lubricant 75, such as glycerine, may be placed in the grooves so as tolessen the friction of the stopper against the side walls of the ampule when it' is moved. 7 A central recess 76 is also depressed lips 79. The metallic washer 77 is joined to the body 7-1 at the time of moulding the stopper and the lips 79 extend into the body 71 and maintain the washer in position on the boss 7 3.

To prepare the ampule 55 for use in my improved syringe 10 the bulbous portion 59 is broken ofi at-the etching 66 and a probe 80 is inserted through the opening at the constriction 58 as shown in Fig. 8.

The probe 80 is shown in'detail in Fig. 10 and preferably comprises a solid metal stem 81 having a recess 82 therein at one end, into which radially disposed apertures 83 form a passageway from the outside. Une end of a hollow reduced needle 84 is inserted and secured in the recess 82 and the opposite end of the needle is preferably sharpened as at 85. The needle 8 1 is of a size to pass through the aperture 78 in the washer 77 and the recess 7 6 of the stopper but the stem 81 will not pass through the aperture in the washer but will abut the washer 77..

When the probe 80 has been inserted into the compartment 56 it is moved downward, so that the needle 84 fractures and passes through the metallic partition 63 into the recess 76 of the stopper, through the solid portion of the stopper and into the compartment 57 as clearly shown in Fig. 5.

When the needle 84 has sufficiently entered the compartment 57 it will be stopped by the end of the stem 81 abutting the washer 76'. The needle 84: extends a certain predeter mined distance from the end of the stem 81 so that when" the stem abuts the washers'67 it is sufiiciently clear of the body of the stopper to allow the vehicle contained in the compartment 56 to be drawn by the vacuum in the compartment 57 through the aperture 83, into the drug compartment 57, thus mixing the vehicle 69' and the drug into a single solution as shown in Fig. 8. I

. After the vehicle and-the drug have been mixed the probe is withdrawn and the compartment 56 is separated from the compartment 57 at the etching 67. The tip 62 is then separated from the compartment 57 at the etching 68 and the compartment- 57 is then ready for use as an ampule in my syringe 10.

The insertion and operation of thisampule 55 in the syringe 10 is the same as that previously described in connection with ampule 35.

In Fig. 3 the small ampule shown at 87 illustrates the wide range of sizes with which my syringe 10 will coact. When a small ampule is used in my improved syringe it is not necessary to remove the centering device 26 and the plunger rod 30 when inserting or removing the ainpule from the syringe as the ampule may be inserted or removed through either of the apertures 14 in the barrel 11.;

From the foregoing description it will be apparent that I have provided a novel form of hypodermic syringe which can be economically manufactured, which is slmple in construction and highly efficient in use.

Having thus described my invention, I claim:

1. In a syringe adapted to receive an ampule, a barrel, an ampule positioning member adapted to move longitudinally in said barrel, said positioning member having frictional engagement with the inner wall of said barrel, a recess in one face of said positioning member and a plunger movable in said barrel.

2. In a syringe adapted to receive an ampule, a barrel, a cap for one endott said barrel, a tip removably secured to said cap, said tip having a cup shaped member positioned in said cap and having an aperture extending from said cup to the end of said tip, an ampule in said barrel, said ampule being constricted at one end, means to provide a fluid tight joint between said ampule and tip and means to hold said ampule to maintain the seal.

3.. In a syringe adapted to receive an ampule, a. barrel, an ampule positioning member movable longitudinally in said barrel, said positioning member having frictional engagement with the side walls of said barrel, a recess in one face of said positioning member, a cap for one end of said barrel, a tip removably secured to said cap, said tip including a tapered recess and an aperture extending from said tapered recess, an ampule in said barrel, said ampule being constricted and open at both ends, a resilient collar adjacent one end of said ampule, said resilient collar being adapted to be positioned in said recess of said tip, said positioning means being adapted tobe moved into contact with said ampule and maintain said resilient collar in said tapered recess of said tip.

4. In a syringgadapted to receive an ampule, a barrel, an ampule positioningmember adapted to move longitudinally in said barrel, said positioning member having frictional engagement with the sidewalls of said barrel, a recess in one face of said positioning member, a cap for one end of said barrel, an ampule in said barrel, said positioning memher being movable into contact with said ampule to maintain said ampule in position.

5. In a syringe adapted to receive an ampule, a'barrel, an ampule positioning member adapted to move longitudinally in said barrel, said positioning member having frictional engagement. with the side walls of said barrel, a recess in one face of said positioning member, a plunger rod associated with said positioning member, said plunger rod being adapted to move longitudinally in said positioning member and in said barrel, an apertured portion at one end of said barrel, an ampule in said barrel, said ampule being constricted at one end, a resilient collar adja cent one end of said ampule, said resilient collar being adapted to be positioned in said aperture, a stopper in said ampule, said positioning member being adapted to be moved into contact with said ampule and said plunger rod being adapted to enter said am? pule and engage said stopper. Q

6. In a syringe adapted to IQCQlWB an ampule, a barrel, a plunger rod movable longitudinally in said barrel, an enlarged head on said plunger rod, said plunger rod having a recess adjacent said head, a cap for one end of said-barrel, a tip in said cap, said tip including arecess and an aperture extending from said recess to the end of said tip, an

am ule in said barrel, said ampule being open .at 0th ends, a resilient collar adjacent one end of said ampule, said resilient collar being adapted to be positioned in said recess of said tip, a stopper in said ampule opposite to said collar and adapted to be moved towards said collar, a disk on one face of said stopper, said disk including aprojecting boss, said plunger rod being adapted to enter said ampule and engage said stopper, said boss on said stopper being, when said plunger rod engages said stopper, positioned in said recess in the end of said plunger rod.

7. In a syringe adapted to receive an amr pule, a cylindrical barrel, a combined closure and ampule positionin member movable longitudinally in said barrel, said closure and positioning member being cylindrical, a plunger rod associated with said positioning member, an ampule in said barrel, :1 resilient gasket coacting with said ampule, a stopper in said ampule, said positioning member being adapted to be moved into contact ARTHUR E. SMITH.

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